What could be wrong with my van? It began squealing about a month ago. on 2003 Kia Sedona

Today it began to bog down and would barely go over 30. It chugs and acts like it does not want to run at all. The squealing is worse and it is getting gas. When in park it revs perfectly. This only happens when I am driving it.

Asked by for the 2003 Kia Sedona
Too many differant things could cause your problem. I would be guessing and that won't help you. Best thing to do is take it to a good repair professional that you get referals about from friends, coworkers, etc.